The present invention relates to screw strips adapted for use in screwing operations of screwing tools or machines, and is particularly directed to such screw strips and methods for making the same wherein a strip or belt of material is formed into sleeves, which at least partially surround the screw threads and are interconnected by ribs or the like.
In the past, screw strips for interconnecting screws have been formed of a retaining belt or strips of breakable plastic material. When a screw strip of this type is inserted in a conventional manner in the flat magazine of a screwing appliance or machine, the first screw to be screwed into a workpiece, along with a portion of the retaining strip, is separated from the screw strip by a screw blade, in the direction of the workpiece. The screw is then screwed into the workpiece. Parts of the separated retaining belt or strip thus drop onto the surface of the workpiece. Some of these parts may fall underneath the head of the screw, and thereby be pressed into the surface of the workpiece. Other parts of the broken strip fall loosely to the surface of the workpiece, and can be pressed into the surface of the workpiece when the screwing appliance or machine is moved, for example, for the next screwing operation. It is apparent that such dropping of the parts of the strip onto the workpiece is disadvantageous, and may result in damage to the surface of the workpiece. This is particularly true when the screwing appliance is employed for inserting screws in holes on the planed and sanded surfaces of furniture. In addition, the broken particles of the retaining strip can settle in the guide channel of the screwing tool when the machine is moved, for example, for the next screwing operation. It is apparent that such settling of the parts of the strip in the guide channel of the tool is disadvantageous and may result in damage to the screwing tool. In addition, the broken particles of the retaining strip can settle not only in the guide channel of the tool as mentioned above, but also in the front parts of the screw magazine whereby jamming may occur thus hampering the operation of the screwing tool.
When the screw strip is formed of a breakable plastic material, once the sleeve has been broken by the screw blade, it can no longer safely guide the screw in the cylindrical guide channel of the screwing appliance. As a result, the screw can tilt and thereby be screwed into the workpiece at an angle. In order to prevent such tilting of the screws, it has been necessary to provide guide jaws in the screwing appliance near the guide channel. Such guide jaws increase the costs of the screwing appliance, and are also subject to wear and breakdown.